1. Field of Invention
The present invention relates to a mobile network; and more particularly relates to a mobile network for handling multiple subscribers having the same calling line identity.
2. Description of Related Art
FIGS. 1A and 1B respectively show the basic elements of a high-level system architecture of a known Universal Mobile Telecommunications System (UTMS) generally indicated as 10 and a known Public Land Mobile Network (PLMN) generally indicated as 20 that together provide a backdrop for understanding the subject matter of the present invention.
In FIG. 1A, the UTMS has User Equipment (UE) 12, a UMTS Terrestrial Radio Access Network (UTRAN) 14 and a Core Network 16 coupled by known interfaces Uu and lu. In FIG. 1B, the PLMN 20 includes the UE 12, the UTRAN 14 and the CN 16 shown in FIG. 1A coupled to external networks generally indicated as 18, including either another PLMN, Public Switched Telephone Network (PSTN), Integrated Digital Services Network (ISDN) etc., all generally indicated as 18a, as well as the Internet generally indicated as 18b. The UE 12 is known in the art and contains a Universal Subscriber Identity Module (USIM) 12a and Mobile Equipment (ME) 12b. The USIM 12a is a known smart card that is arranged in the ME 12b, holds the subscriber identity, performs authentication algorithms and stores authentication and encryption keys and other information that is need by the ME 12b to interact with the PLMN 20. The ME 12b is also known as a mobile station (MS), which may include many different types of mobile electronic devices such as a mobile phone, a personal digital device (PDA), a laptop computer, etc. The UMTS Terrestrial Radio Access Network (UTRAN) 14 is also known in the art and contains one or more nodes B (i.e. base stations) 14a in combination with one or more Radio Network Controllers (RNC) 14b, that combined to provide a known radio interface between the UE 12 and the CN 16. The CN 16 is a combination of high-capacity switches and transmission facilities that form the backbone of the PLMN 20 in FIG. 1B. The CN 16 includes a Mobile Services Switching Center/Visitor Register Location (MSC/VLR) 16a, a Home Register Location (HLR) 16b, a Gateway Mobile Services Switching Center 16c, a Serving GPRS Support Node 16d, and a Gateway GPRS Support Node (GGSN) 16e, which are all known in the art.
Recently, some networks, such as the PLMN shown in FIG. 1B, have introduced new features providing Same Calling Line Identity (CLI) for multiple subscribers (MS1, MS2, MS3 in FIGS. 2A and B) and allowing incoming calls and SMS arriving with this same CLI to be sent to an appropriate MS. This is part of a Multi-SIM subscription concept. The principle is that the user (subscriber) may have multiple mobile stations (MS) (e.g. one handheld and one in the car) and they will all use the same identity when they originate calls or short messages. In addition, incoming calls and SMS reach the right MS. Calls could for example use sequential ringing (if a first MS does not answer, the call is transferred to second MS and so on) or simultaneous ringing. An SMS is typically sent only to the primary phone. This solution is based on the fact that a respective SIM card, like the SIM card 12a (FIG. 1B), is inserted in each MS, and that this SIM card 12a has its own or individual International Mobile Subscriber Identifier (IMSI) and its own or individual Mobile Subscriber ISDN Number (MSISDN). The IMSI is understood to represent the SIM card number, while the MSISDN is understood to represent the phone number of the MS. The MS also has an individual International Mobile Equipment Identity (IMEI) associate with it, which is understood to be a unique manufacturer number assigned by the manufacturer of the MS. As shown in FIGS. 2A and B, the individual IMSI number (IMSI1, IMSI2, IMSI3) and MSISDN number (MSISDN 1, MSISDN 2, MSISDN 3) are registered in the HLR 16b, 16b′ under a subscription profile of the PLMN 20. Additionally, each of these subscription profiles (subscriber profile 1, subscriber profile 2, subscriber profile 3) also has a so-called common MSISDN number, which can be used to replace the individual MSISDN. This way the PLMN 20 that is visited by a MS can receive the common MSISDN of the visiting MS instead of the individual MSISDN during a location updated procedure related to the visiting MS. There are two alternatives for storing the subscriber profiles in the HLR:                One of the subscriber profiles in the HLR 16b also has an identical individual and common MSISDN numbers, such as subscriber profile 3 in FIG. 2A, and this subscriber is referred to as a so-called primary subscriber, while the mobile phone, which contains that SIM card (IMSI), is referred to as a so-called primary phone.        Another implementation alternative is none of the profiles have identical individual and common MSISDN number as shown in FIG. 2B. The common MSISDN number identifies a list of members, so called group. One member of the group can be selected as a primary member. In this case, the terminated transactions with the common MSISDN number can be routed further from the group to the primary member with the help of a stored individual identifier of the primary member. The primary member of the group is referred to as a so-called primary subscriber, while the mobile phone, which contains that SIM card (IMSI), is referred to as a so-called primary phone.        
The way this feature presently handles a Short Message Service (SMS) message is noted. For example, the SMS message sent to the common MSISDN is only provided to the primary phone. In comparison, the non-primary phone will receive the SMS message only if sent to its individual MSISDN. A common MSISDN and/or individual MSISDN may be sent from the HLR 16b to the VLR 16a, or the SGSN 16d, depending if the VLR 16a or SGSN 16d supports the feature. It should be noted that the feature is described regarding MSC/VLR but is also applicable to SGSN because an SGSN sends and receives SMS exactly like the MSC/VLR. As shown, the VLR also stores the IMEI of the MS.
One problem with this new CLI feature is that it conflicts with the remote MS configuration performed by a Terminal Management Server (TMS) 30 shown FIGS. 2A and B in the PLMN 20 when the MS visits a new PLMN.
Currently, in operation when the MS visits the new PLMN, the MS provides its IMSI number to the MSC/VLR 16a of the visited PLMN. In addition, the MS also provides an IMEI to the MSC/VLR. For example, FIGS. 2A and B shows three mobile stations MS1, MS2, MS3 providing their respective IMEI numbers, IMEI1, IMEI2, IMEI3, to the MSC/VLR 16a upon visiting the PLMN 20. In this case, the MSC/VLR 16a informs the TMS 30 of the new IMSI/MSISDN/IMEI combination. When the TMS 30 detects that a new MSISDN is not yet configured, it will derive from the IMEI the mobile type of the MS, and send the proper configuration to the visiting MS through the SMS message.
In operation, if the MSC/VLR 16a uses the Same CLI for the multiple subscribers feature, the TMS 30 may receive the common MSISDN and a non-primary MS IMEI. The TMS 30 will then attempt to configure this IMEI, but the SMS message addressed to the common MSISDN will reach the primary MS (subscriber profile 3). In view of this, the primary MS will then be misconfigured, and the non-primary MS will not be configured at all.
If the MSC Same CLI feature for multiple subscribers is used, the TMS 30 has no mechanism to determine if the received MSISDN is the individual MSISDN of the MS or the common MSISDN of the MS, and so it cannot use it for remote configuration of the visiting MS.